[semi-extrinsic]

I agree, this paper smells strongly of someone who has not actually spent the time required to read and understand the current state of the art on QFT, and is just reading papers from 50 years ago to find things they didn't understand correctly then.

And he is completely missing one of the biggest drivers in modern physics: you have basically an army of researchers trying desperately to find something, anything that is provably wrong with QFT. Because we know it's not the final theory, something is missing, and finding concrete errors might very well show us the way to a better theory.

If, as the author claims, some original Feynmann diagram calculations are "kept secret" and actually wrong, all it takes is one postdoc somewhere to actually redo the calculations and show the error for all the world. That's a career defining paper right there, something that would make you famous in the community. If people thought there was even a 0.01% chance that was the case, they would be chasing it hard.